AIC/BIC for TwoStage Model

For example I have a dataset with 100 patients and I performed a two stage fitting using a) 1-compartment model b) 2-compartment model. To calculate the total loglikelihood (LL), I can just add the LLs for all 100 fits that I get and compare a and b, but I have a feeling that I we cannot add the BICs or AICs like LLs for all fits. Is there a rational way to get a “total BIC/AIC”? Thank you!

I don’t think AIC/BIC add up as the individual log-likelihoods do